Lens edge-grinding, finishing and beveling machine

ABSTRACT

A compact machine is provided for grinding, finishing and beveling the edges of lenses to a pattern size and edge shape. A sizing cam permits control of size to any desired fine adjustment, with complete accuracy. The grinding of a lens blank to a selected pattern is controlled by a master cam which guides a work carriage both for grinding the lens to pattern and size, and for finishing and beveling the edge to any desired bevel center. The lens grinding operation from start to finish is completely automatic, and fully controlled, and the machine automatically comes to a halt when the lens has been shaped and ground to the selected pattern and size.

[ July 17, 1973 United States Patent [1 1 Savage 2,970,409 2/1961 Selng51/1011 3,321,870- 5/1967 Bolden............................51/216 LPMilton B. Savage, 1780 E. 9th St., Brooklyn, NY. 11223 Sept. 2, 1970Primary Examiner-Harold D. Whitehead Attorney-lanes and Chapman 221Filed:

[57] ABSTRACT A compact machine is provided for grinding, finishing andbeveling the edges of lenses to a pattern size and Appl. No.: 69,080

Int. B24b 9/14 edge shape. A sizing cam permits control of size to any[58] Field 01 desired fine adjustment, with complete accuracy. The

grinding of a lens blank to a selected pattern is con- [56] ReferencesCited trolled by a master cam which guides 21 work carriage UNITEDSTATES PATENTS both for grinding the lens to pattern and size, and forsum finishing and beveling the edge to any desired bevel 5 won center.The lens grinding operation from start to finish 5 is completelyautomatic, and fully controlled, and the 51/101,1 machine automaticallycomes to a halt when the lens 5 1/ 101.1 has been shaped and ground tothe selected pattern and 5l/l01.l size ....51/101.l

6/1956 Connell........................,..,.. 51/101 1 37 Claims, 14Drawing Figures 598 5/1970 Asselin............................... 2061/1964 Baumgartner 415 411967 Lannon............

567 3/1948 Uhlemann....

312 2/1941 l-larrold........

172 7/1967 Stern.........

622 5/1929 Rabel.......

m m a??? PATENTED JUL 1 7 I975 SHEEIIUF? PATENIEU JUL 1 1 ma SHEET 2 [If7 'PATENTEDJUL 1 7191s SHEET 3 [1F 7 PATENIED Jun 1 3'. 745 720 SHEET 50F 7 PAIENIED H 3.745.720

' SHEET 6 [If 7 LENS EDGE-GRINDING, FINISHING AND BEVELING MACHINEEyeglass lenses today are rarely round, but have to be ground to order,to fit a variety of eccentrically shaped spectacle frames designed tosuit individual tastes. It is impractical to have in stock eyeglasslenses of the range of prescriptions normally encountered to fit anyparticular frame. Instead, the optometrist or optician has on hand astock of eyeglass blanks, which are then edge shaped and cut to fit theindividual frame requirements of the user. This means that the averageoptometrist or optician must have available suitable lens grinding andshaping equipment.

Usually, such equipment is housed in a small shop in a corner of hisestablishment. The space available for such equipment, and the necessitythat it be simple enough to be operated by one lacking in mechanicalskills, impose a need for lens grinding equipment that is both compactand simple to operate and maintain. However, the commercialmanufacturers of such equipment have tended to develop machines ofgreater and greater complexity and size, in seeking to impose featureupon feature, for greater sales appeal, with the result that theavailable machines are never simple, and are rarely easy to maintain.

The recent patents in this field give a suggestion of the complexity ofdevelopment of this type of machine. U. S. Pat. No. 3,332,172, to Stern,patented July 25, 1967, describes an automatic edger which is capable ofperforming multiple finishing operations on lenses from a single set-upof the lens in the machine. However, the machine has three motors, motor106 for the finishing means 18, motor 60 to drive the shaft 40, andmotor 156 todrive the cam shaft 152, all of which are controlled byseparate control switches. There are also a host of cams, forcontrolling the sequence of operations, including eccentric cam 92, cam140, cam 170, and the cam surfaces on cam shaft 152.

Whether complex or simple in construction, the available lens grindingmachines nonetheless have similar basic components. A lens holder isprovided, which is capable of holding the lens blank to be ground forrotation during the grinding about a selected transverse axis usuallythrough the optical center of the lens, and which is itself mounted on acarriage arranged to move along this axis. Two lens-edge trimming wheelsare provided, one flat, with a coarse surface, which cuts the lensquickly to the desired size and shape, and is referred to as thegrinding or flat wheel, and the second, grooved with a fine grindingsurface, which accomplishes the beveling and finishing or polishing ofthe lens edge, and is referred to as the finishing or beveling wheel.The lens-holder and associated parts are referred to as the lens head,and this is arranged to pivot about an axis parallel to the transverseaxis of the lens, so as to move the lens blank into and away fromcontact with the grinding and beveling wheels. The size and shape of thelens are controlled by a pattern cam, which is mounted for rotationabout a transverse axis which is the same as that of the lens and is ata sizedetermining distance from the grinding wheels. The pattern cammoves against a fixed surface, the pattern platform, which fixes at apredetermined minimum the distance between the axis of rotation of thelens and the grinding wheels, and thus controls both size and pattern.The size of the lens can be changed by changing the position of thepattern platform with respect to the transverse axis through the lens,and the grinding wheels determine the actual size of the lens withoutregard to the size of the template, since the platform spaces the lensat a fixed minimum distance from the grinding wheels. Rotation of thepattern or template on the platform thus controls both the size and theexternal configuration of the lens.

The lens-holder is arranged to hold the lens blank in a stationaryposition, without rotation, in contact with the grinding wheel, untilthe desired size and shape has been ground out, at each rotationalposition of the lens. The pattern cam actuates rotation according tocontact thereof with the pattern platform. Thus, the lens blank is heldin each position until its edge has been ground down enough to permitsuch contact. Contact actuates an electrical circuit which in turncauses the lens to rotate to a new position. When the size and patternhave been cut, all around the periphery of the lens, the carriage ismoved over so that the lens edge rides in the groove of the bevelingwheel, and the lens is allowed to float freely on this wheel, to obtainthe desired bevel. Usually, the lens is allowed to rotate through one orseveral turns, to ensure that the edge is fully cut, and conformsperfectly to the pattern.

One problem with the available lens grinding machines is the mechanismfor control of the size of the lens. Usually, this is done by raising orlowering the pattern platform. However, unless the position of theplatform can be exactly controlled, and correlated with a given size,the sizing cannot be done accurately. Many machines use a threaded dialcombined with a threaded pattern rest shaft. The difficulty with thisapproach is that one revolution of the dial cannot be made to giveaccurately the necessary number of sizes. One revolution may give manysizes, but cannot accurately give the full range, so that severalrevolutions are necessary. If calibration becomes necessary, the sizesare even more difficult to determine. Moreover, with wear, play developsbetween the threads of the dial and of the vertical shaft, and thiscauses a further discrepancy in size, since a slight rotation of thedial may not cause an immediate change in the height of the patternplatform. Moreover, vibration of the machine may cause the size to vary,because there is no way of positively holding a loose size setting in agiven position.

In existing machines, it is also difficult to control the position andcontour of the bevel. For appearance purposes, it is not alwaysdesirable to have the lens finished with a centered bevel, i.e., withthe apex of the bevel midway between the front edge and the back edge.lf the lens is thick, the appearance is always better when the thicknessis concealed behind the frame, which can be accomplished if the bevel isdisplaced towards the front of the lens. To obtain an eccentric bevel,pressure must be applied against the front of the lens during thebeveling cycle, to grind more away from the rear side. This pressuremust be relieved before the lens starts to lift away from the bevelingwheel at the end of the cycle, because if it does not, the pressure willcause the lens to hit the side of the beveling wheel, and grind part ofit away. The available machines use a solenoid to relieve the pressure(which is applied using a weight) at the correct moment. Other machinesemploy heavy springs, to snap the lens head up quickly, at the end ofthe cycle, and thus remove the lens from the beveling wheel. Solenoidsmay go out of order, however, and

heavy springs tend to lose some of their tension in use, and have to bereplaced frequently, for accurate control.

The various movements of the lens both towards and away from thegrinding and beveling wheels and sidewise with respect to the wheels arenormally controlled by cams. These control the dropping of thelenscarrying head down onto the grinding wheel, lifting the head awayfrom this wheel, moving the head and the lens over to the bevelingwheel, dropping the head and lens down onto the beveling wheel, applyingand removing pressure at the proper time for bevel control, lifting thehead and lens at the end of the beveling cycle, and moving the head andlens back over the grinding wheel in readiness of the next cycle.Needless to say, the more cams, the more opportunities there are formalfunction, and the more opportunities there are for wear. Moreover,the wear may be uneven on various cams, sometimes requiring replacementof some cams earlier than others. If some are replaced, but not all,this always means that the various cams are at different wear rates,with varying degrees of accuracy during the several stages of thegrinding and beveling operations.

During the grinding operation, the lens must be kept cool, and thisrequires application of a coolant spray, to lubricate the lens edge andfacilitate the grinding and polishing. The resulting fluid materialstend to travel all over the equipment, and unless provision is made,such material can cause unnecessary wear, because the fluid picks upground glass sediment from the lens. Moreover, the sediment can cakeupon evaporation of the fluid, which can result in malfunction, ifdeposits accumulate in and among moving parts.

The available machines also leave much to be desired in accessibility tovarious parts of the equipment, for replacement of worn parts, forcleaning operations, and for retrieval of broken pieces or wastematerial, including broken lenses.

Another serious problem is the lens holder. This must hold the lensblank firmly against rotation during the grinding operation, but at thesame time it must not apply so much pressure that the lens can be brokenor cracked during the grinding, or during the beveling operation, inwhich it rotates freely. A friction grip is the most practical one, butit will be appreciated that to fixedly grasp an odd-shaped surface in afriction grip requires a rather flexible holder, and this flexibilitymust not impair the friction grip. A large lens blank requires a largefriction grip, but if the finished lens is small, there is too littleroom on the lens surface to apply on a large friction grip.

Most lens holders are round, but the final shape of most lenses isusually larger in the horizontal direction than in the verticaldirection. Thus, when the finished lens size is small, often the holderitself is ground away on the vertical side.

In accordance with the invention, a lens edgegrinding, beveling andfinishing machine is provided, which is extremely simple inconstruction, and which is completely automatic from the start to thecompletion of the grinding, beveling and finishing operation. Themachine employs one motor to operate the grinding, beveling andfinishing wheels, and one motor for all other movements, and features amaster cam of special design for complete operational control of thegrinding, beveling and finishing cycle, while using a conventionaltemplate cam to control pattern shape and size. Another feature is aspiral cam size adjusting mechanism, to position the pattern platformwith complete accuracy, and a locking mechanism associated with the sizesetting means to prevent the platform from slipping into a differentsize position during use, all in a manner which minimizes wear. Furtherfeatures are a housing with a completely enclosed lens-grindingcompartment that retains a coolant and particles of ground glass, andprevents contamination of other moving parts therewith, and is readilyaccessible both for changing lenses and for cleaning; pressure controlmeans for applying pressure during the beveling and finishing operation,to displace the bevel center in any desired direction; a lens holder orchuck that can hold the lens without slippage and without grinding theholder or chuck body away; a lens blank of virtually any type and degreeof curvature at its center, regardless of the size of the finished lens,throughout the grinding, beveling and finishing operations; and anelectrical circuit that controls all operations during a cycle on afail-safe basis, with an automatic shut-off at the end of the cycle.

The master cam has a plurality of cam surfaces which establish andcontrol each of the various steps of the grinding and bevelingoperation, as follows:

1. Pivotal movement of the lens-carrying head and lens towards and awayfrom the grinding wheel.

2. Transverse or sideways movement of the lenscarrying head and lensfrom opposite the grinding wheel to opposite the beveling and finishingwheel, and back.

3. Pivotal movement of the lens carrying head and lens towards and awayfrom the beveling and finishing wheel.

4. Holding of the lens-carrying head and lens against transverse orsideways movement during the grinding, and allowing such movement duringthe beveling and finishing.

5. Application of and removal of pressure to the lens during thebeveling and finishing, so as to control the beveling eccentricity.

6. Shut-off of the electric circuit at the end of a grinding andbeveling and finishing cycle.

Functions (1) and (3) are provided by one cam surface, functions (2) and(4) are provided by a second cam surface, and functions (5) and (6) by athird and a fourth cam surface, all combined on the same cam. The cam isin the form of a cylinder, having four adjacent sections, which may be apart of one cylinder, or four cylindrical segments attached for rotationtogether. The cam mounted on a camshaft which is motor-driven, and thesame motor can drive the camshaft and the lens holder shaft, in asynchronized operation.

Each cam surface has an associated cam follower. The first cam followeris operatively connected to the lens-carrying head, and pivots it aboutan axis parallel to the axis of rotation of the lens. One of the secondcam follower or the second master cam surface is operatively connectedto a movable carriage on which the lens-carrying holder is mounted, andactuates transverse reciprocating movement thereof, first in onedirection, and then back, between limiting positions corresponding topositions of the lens opposite the grinding wheel and the beveling andfinishing wheel, respectively. The third cam follower is operativelyconnected to the pressure-applying means, to move it into and out of apressure-applying position with respect to the lens,

but only while the lens is in contact with the beveling and finishingwheel. The fourth cam follower is in fact a switch control means.

The first and third cam surfaces are eccentric, of the hill-and-daletype, and raise or lower the cam follower to effect the desiredoperation. The second cam surface is provided with a surface groove ortrack, along which the second cam follower rides. One portion of thegroove is just wide enough to accommodate the cam follower, to hold themovable carriage on which the lens-carrying head is mounted in a fixedtransverse position while the lens is in contact with the grinding wheelduring one portion of the cycle, and another portion is wide enough topermit free transverse movement of the movable carriage while the lensis in contact with the beveling wheel, during another portion of thecycle.

The fourth cam surface is a small segment, holding a pressure-operatedbutton of an electric switch in an off position while in contacttherewith, and in all other positions allowing the button to remain inan on position.

The size of the lens, in the apparatus of the invention as in otherconventional apparatus, is controlled by raising or lowering the patternor template platform. When the platform is raised, the lens-carryinghead is prevented from dropping any closer than a predetermined minimumdistance from the grinding wheel, thus fixing a minimum size for thelens. Thus, when the platform is raised, the size is increased, and whenthe platform is lowered, the size is reduced. The position of theplatform with respect to the peripheral surface of the grinding wheelsis controlled in accordance with the invention by a wheel having aspiral slot, and which is referred to herein as a spiral cam. The wheelis mounted on and rotates about a fixed axis with a camshaft. The spiralcam slot rises helically in a uniform curve from a central part of thecam wheel to its peripheral edge. A cam follower is guided in thisspiral cam slot. The cam follower is fixedly mounted to the platformsupport, and is guided upwardly or downwardly, to raise or lower theplatform support, according to its position in the spiral slot, which isdetermined by the rotational position of the spiral cam.

The sizing mechanism is provided with a sizing dial, with a scaleshowing the sizes of the lenses according to the position of theplatform. The scale can include numbers, markings, gradations, etc., sothat a given beveling position of the scale can be selected according tothe lens size desired. Accurate communication of this position withrespect to lens size, and locking of the platform in any selected sizeposition, are obtained in each lens size gradation on the size scale ofthe sizing of the platform cam follower in the slot thereof, and theplatform. The sizing dial has a locking means such as an internal gearor a plurality of projections or pins meshing with and locking into thecam lock, such as the toothed periphery or apertures thereof. Thus, therotational position of the spiral cam is reflected exactly by theposition of the sizing dial, and when the sizing dial is locked to thecam lock by the locking means, the dial cannot be rotated. The cam lockhas a fixed position for each position on the dial Biasing means isprovided, to keep the sizing dial normally in locking engagement withthe cam gear.

The sizing dial is slidably mounted on a square shaft (although anyother polygonal configuration can be used), so that when it is rotated,it will also rotate the spiral cam, and it can also be moved on thecamshaft both away from and into engagement with the cam lock, againstand with the biasing force of the biasing means. Thus, when the size hasto be changed, the dial has to be unlocked, before it can be turned. Todo so, the dial is pulled away from the cam lock, releasing it, afterwhich the dial is rotated to the proper size, and then allowed to returninto its normal locking position on the cam lock by the biasing force,whereupon it is lockedin place, preventing further rotation of the spifral cam. In this way, size control is exact, and the plat form is alwayslocked in the selected size position Further details of the lensedge-grinding, finishing and beveling machine of the invention willbe'apparent from the following description and the drawings, in which;

FIG. 1 represents a plan view, seen from above, with parts cut away, ofthe top of one embodiment of machine of the invention;

FIG. 2 represents a side view, with parts cut away, of the machine ofFIG. 1, showing the size control dial, the pattern cam, the master cam,the beveling pressure control mechanism, and the size control supportarm;

FIG. 3 represents a front view, with parts cut away, of the machine ofFIGS. 1 and 2, showing the sizing dial, spiral cam, and master cam onthe left of the drawing;

FIG. 4 is a top view of the machine of FIGS. 1 to 3, with the lens-headcover and movable carriage cover removed, exposing the drive mechanismfor the lens holder and also showing the drive mechanism for thegrinding, beveling and finishing wheels;

FIG. 5 is a rear view of the machine of FIGS. 1 to 4, with parts cutaway, to show the motor and camshaft for the master cam, the motor forthe grinding, beveling and finishing wheels, and electrical connections,the two shafts of the movable carriage, and the bearing supports onwhich the movable carriage slides transversely, and upon which are heldthe size control sup port arm, and the beveling pressure control arm;

FIG. 6 is a detailed side view on an enlarged scale of the spiral camand cam lock mechanism, controlling the position of the pattern platformand pattern cam;

FIG. 7 is a detailed vertical section on an enlarged scale taken alonglines 7-7 of FIG. 6 showing the spi ral cam and cam lock mechanism andthe microswitch controlling operation of the lens rotating mechanism;FIG. 8 is a developed view, on an enlarged scale, of the four master camsurfaces;

FIG. 9 is a detailed front view partly in section on an enlarged scaleof the lens holding mechanism;

FIG. is a detailed sectional side view, on an enlarged scale, of thelens holder segments;

FIG. 11 is a detailed side view, on an enlarged scale, taken along lines11-11 of FIG. 10, showing the left lens holder;

FIG. 12 is a detailed cross sectional view, on an enlarged scale, of thelens holder segments;

FIG. 13 is a detailed rear view, on an enlarged scale, of the master camsection and cam follower; and

FIG. 14 is a detailed side view on the same scale as FIG. 13 of themaster cam section and cam follower.

The apparatus shown in FIGS. 1 to 11 has a base 1 which supports theentire machine, and is fitted with lugs 2 to carry screws 3 for levelingor attachment on a platform, table or other support 4 to position themachine at a convenient height for use.

Mounted on base 1, at the front, is a tank or container 6, with aremovable door 7 which gives access to the interior of the tank 6, forcleaning purposes The door 7 has a peripheral flange 9 engaging amatching flange 10 in the tank 6, and is held in place against theflange 10 by the latch bolt 11. The latch bolt is slidably held in thepierced lugs 12, and releases the door when it is slid out. The tank 6can also be provided with a drain 133. at the bottom.

At the rear of tank 6 are fixed two pairs 13, 14 of lugs, each of whichhas through apertures in which are supported linear motion ball bushings18 such as Thomson ball bushings. These carry a movable carriage 90,which is supported as follows:

Two shafts 91, 92 extend through the bushings l8, and slide thereintransversely, but do not rotate therein. The ends of shafts 91, 92support side plate supports 13', 14' of the carriage 90, and these inturn carry the various components of the machine that form a part of thecarriage. The sideways movement of the carriage on shafts 91, 92 inbushings 18 is controlled by a master cam 20, as will presently be seen.

In an alternative embodiment, the ball bushings can be fixed in the sideplate supports 13', 14, and the carriage 90 can slide on the shafts 91,92, and the shafts fixed to the lugs l3, 14.

The carriage 90 carries a lens head housing 5, pivotably mounted on ashaft 77 which extends through and is supported by the side platesupports 13', 14'.

The carriage 90 has a cover 16 on which is mounted hinged lens cover 19by screws 17. The cover 16 protects the moving parts enclosed by thecarriage housing. The cover 16 is removable, and when in place serves asa brace for the carriage structure and side plate supports 13', 14'. Thehinged lens cover 19 fully encloses the lens holder and any lens heldtherein. The hinged support of the cover provides ready access to thelens compartment 8 of housing 5, for insertion of a lens blank andremoval of a finished lens.

Two shafts 21, 22 are supported in and extend through the side walls 23,24 of the lens holder housing 5, which with the interior side walls 23',24' define lens compartment 8, respectively. The end 25 of shaft 21extends into the lens compartment from one side, while the end 26 ofshaft 22 extends into this compartment from the other side. Each shaftend supports one of the two segments 27, 28 of the lens holder.

Each segment of the lens holder is smaller than the smallest size lensto be shaped, is roughly octangular in shape, with rounded comers, andis fixed with the long side horizontal to the shaft ends 25, 26. Segment27 presents a concave surface, and segment 28 a convex surface, to thelens held therein. The long axis of each segment corresponds to the longaxis of the finished configuration of the lens, or what is known as theline.

These are shaped for grasping a curved lens. They can each be flat,also, to grasp a flat lens, and each machine would normally be fittedwith a set of each type, to be able to handle each kind of lens.

The lens holder of the invention although small is shaped to fit anysize lens, and will grip the lens firmly without slippage because thefrictional hold is maintained over a large horizontally oriented area,but with less interference vertically. There is therefore no likelihoodthat the grinding wheel will grind away part of the holder after thelens has been cut to size. This is achieved by the octagonal shape, andby the following structural features.

Each holder segment has a body portion 29. Segment 28 and a chuck 27a ofsegment 27 each have a circular socket 30 to receive the shaft end 25 or26, and a locking slot 31 receiving the pin 32 on the shaft ends. A rim33 extends along the central horizongal sides 34 of each of the holders,and retains a felt pad 35. Each felt is shaped to the surfaceconfiguration of the holders, and has a central cavity 36. The felt padsare bonded to the surface with cement. The pads conform in curvature tothe holder surfaces, and thus lens holder 27 presents a concave felt padsurface to the lens, and lens holder 28 presents a convex felt padsurface to the lens. The central cavity 36 of each pad makes it possiblefor the pad to provide pad friction gripping contact with maximumgripping force with the lens periphery and minimum gripping force at thelens center to hold the lens in the proper position during grinding,finishing and beveling without undue pressure at the lens center, whichis particularly important for holding lens blanks which are very thin attheir center.

The lens holder segment 27 is removable. The chuck portion 27a has twopins 27b that fit in corresponding apertures 270 in the segment body 29.The lens seg ment is removed, a lens blank (held in a conventional lensblank clamp) is carefully fitted in the concavity so that its opticalcenter is at the central axis of the segment, and the composite thenreplaced on the pins 27b, after which the lens holder segment 28 istightened in place against the other surface of the lens blank, to fixit in position for the grinding, beveling and finishing operations.

The holder segments are so shaped and fixed in position on the two lensshafts that the lens can always be centered therein in any desiredposition with respect to its optical center. This makes it possible toshape the edge of the lens exactly with respect to the lens center,which is important for correct prescription positioning of the lens in aspectacle frame.

Rotatable drive means are provided for each lens shaft 21, 22 in theform of sprocket wheels 40, which can be fixed in any desired locationalong the shafts by set screws 41. The shaft 21 and the sleeve 38through which shaft 22 passes are each rotatably supported in thecentral apertures of a pair of ball-bearing wheels 42. Thepair of wheels42 for shaft 21 are fitted into the lens head housing and the pair ofwheels for shaft 22 and sleeve 38 are fixed within the supporting sleeve44 fixed to the housing walls 24', 24.

A thrust bearing 43 presses against the lens head housing and preventsthe wheel 42 from being pushed out, and prevents binding of the shaft 21or the lens head housing. The shaft 21 and the sleeve 38 (and thus shaft22) rotate on the ball bearings of the wheels 42 when the sprocketwheels 40 are driven by chain drives 75.

The shaft 21 is rotatable within its pair of ball-bearing wheels 42, butcannot be moved in a transverse direc- .tion. Shaft 22 is rotatablewithin sleeve 44, together with sleeve 38, and it also is mounted fortransverse movement within sleeve 38, to provide the access space neededfor removing and inserting a lens between the lens holder segments 27,28. Such transverse movement is provided for by a unique mechanism whichpermits shaft 22 to be locked in any desired position, to fit thin orthick lenses, with the lens-holder segments 27, 28 in a firm frictiongrip on the lens, without danger of breaking the lens.

The sprocket wheel 40 allows transverse movement of shaft 22 withoutcorresponding movement of sleeve 38 because set screw 41 passes througha slot 39 in shaft 22. Consequently, upon transverse movement of theshaft 22, set screw 41 slides freely in the slot. The screw also servesto prevent rotation of shaft 22, except when the sprocket wheel 40 andsleeve 38 are rotating.

The mechanism for releasing and tightening the lens holder segments 27,28 with respect to a lens or lens blank is as follows:

A thrust bearing 45 is mounted within the hub compartment 49a of handwheel 49. The outer end 46a of the shaft housing 46 has an internallythreaded aperture 47, which receives the threaded portion of a tubularlens holder control shaft 48 that supports hand wheel 49. The opencenter 48a of shaft 48 receives therein the end of shaft 22. The shaft22 is locked into the hub compartment 49a by 22a, so that the hand wheel49 can rotate shaft 48 in the threaded socket 47,

but always holds the end of shaft 22 in the compartment 49a, and carriesthe shaft with it in either direction of transverse movement thereof.Thus, rotation of the hand wheel 49 to the right or left moves the shaft22 (without rotation of the shaft, due to set screw 41) towards or awayfrom the shaft 21, so that a lens can be inserted between the lensholder segments 27, 28. The lens can then be fixed in position betweenthe holders 27, 28 by rotating hand wheel 49 to move the segment 28 intoholder-abutting position with segment 27, tightening the shaft 48 in theaperture 47, so as to lock it there, after the lens has been firmlygripped between the holders, while thrust bearing 45 permits rotation ofthe wheel without binding.

It will be seen from FIGS. 3 and 4 that the lens compartment 8 of thelens head housing opens at the front into the tank 6, which extends thefull length of the'lens head housing 5, and serves as a lens-grindingcompartment, In the tank 6 are disposed the grinding wheel 70 andbeveling and finishing wheel 71 which are driven by the motor 135.Particles of glass ground from the lens may collect in the tank 6,together with any coolant fluid sprayed against the lens. The tank canbe cleaned out from time to time; removal of the door 7 gives completeaccess to all portions thereof. When the lens cover 19 is in place, thetank is closed off fully. Consequently, it is impossible for groundglass particles to travel anywhere about the machine; they are confinedto the tank 6. However, even when the cover 19 is up, the interior wall72 and top wall 73 of the lens compartment 8 prevent splash in thedirection of the operator of the machine.

The end 50 of shaft 21 extends out over a pattern platform 51, and theend 50 is shaped to receive, for rotation therewith, a lens pattern ortemplate 122 of conventional type, thus ensuring that the axis ofrotation of the pattern or template will be the same as the axis ofrotation of the lens during grinding, finishing and bevelmg.

The platform 51 is mounted on a vertical shaft 520, which is slidablyheld through the aperture 54 to a pivotable size control support am 53.The shaft 52a is held spaced from a second coaxial shaft 52b by a coilcompression spring 69. The arm 53 is carried on pivot pin 74, held inwall 13 of the movable carriage 90. The top end of the shaft 52a isfixed to the platform 51. The bottom end of the shaft 52b carries acylindrical ball bearing 55, which serves as a cam follower.

A vertical set screw 52c parallel to shaft 52a bears against the top ofshaft 52b, and adjusts and limits the downward movement of shaft-52a.

A cam wheel 56 ismounted for rotation on a camshaft 57 directly belowthe shaft 52b, with its center in line with the longitudinal axis of theshaft. The cam 56 has a spiral cam slot 58, wide enough to receive thebearing 55, which is guided in the slot. The cam wheel is fixedlymounted on the camshaft 57 for rotation therewith. The camshaft 57extends through and rotates in the aperture 59 of the support arm 53.Thus, the radial position of the slot 58 determines the position of theball bearing and with it, the elevation of the shafts 52a, 52b, attachedthereto, and consequently the height of the platform 51 with respect tothe axis of rotation of the grinding and beveling wheels 70, 71.

On the other side of and fixed to the support 53 is a peripherallytoothed cam lock 60. This lock has a central aperture 61 through whichthe camshaft 57 extends. The periphery of the lock can have any desirednumber of teeth, in conformity with the exact number of sizes desired;in the lock shown, there are 144. The lock teeth hold the sizing dialand therefore the spiral cam in any desired fixed position.

Beyond the lock 60, the camshaft 57 has a square configuration, andsupports a slidable sizing dial 62. A sizing knob 63 is slidablyattached to the end of the shaft 57. The sizing dial is attached to theknob, and can be rotated manually by rotating the knob. The knob 63 andthe dial 62 rotate the shaft, and always have the same radial positionas the cam wheel 36, so that their position reflects exactly theposition of the spiral cam slot 58, and therefore of the platform 51.

The sizing dial 62 has an internal recess 64, confonning to the externalconfiguration of and receiving the cam lock 60, and the sizing dial 62and knob 63 can be slid along the shaft 57, so that the dial 62'movesinto and out from engagement with the cam lock. Such movement iscontrolled by the sizing knob.

ln spaced positions along the interior wall of the recess 64 of thesizing dial are four pins 65, which are positioned to mesh with theteeth of the cam lock 60, and when so placed the camshaft 57 is lockedagainst rotation. When the sizing dial is moved to the right, so thatthe cam lock fits within the recess, the pins lock into the teeth. Acoil spring 66 in the dial handle biases the dial towards the lock, soas to keep the pins normally meshed in the teeth thereof, to lock thecam wheel 56 in any selected position. Sliding of the dial to the leftby the sizing knob releases the pins. This permits rotation of thespiral cam and of the sizing knob to a new selected position, and thuspermits adjustment of the platform height to correspond to any desiredsize of a lens by raising or lowering the platform 51 via the camfollower 55 guided by the spiral cam slot 58 of the cam wheel 56, andthe platform can be locked in each selected position by meshing the pins65 in the teeth of the cam lock 60.

A microswitch 67 is attached to arm 53, with its pushbutton 67'extending upwardly. A lug 68 on shaft 52 is positioned to depress thebutton and actuate an electric circuit when the shaft is moveddownwardly against the upward biasing force of coil spring 69, whichoccurs whenever the lens pattern 122 is in position on the end of shaft21, and is resting on platform 51, due to the weight of the lens headhousing and associated parts, transmitted through the pattern to theplatform and shaft. In consequence, the button 67' is depressed and theswitch is on only when the lens edge has been cut down to such a sizethat the pattern 122 rests on the platform. Set screw 52c adjusts andlimits the depression of the button 67' by limiting the downwardmovement of shaft 52a against spring 69.

The switch 67 controls the electric circuit operating the lens drivemechanism for rotating the shafts 21, 22 during the grinding operation.This drive mechanism is a gear drive motor with a brake arrangement toprevent override. The switch is off and the lens is held againstrotation during grinding down to size, because the pattern is elevatedabove the platform during this operation, but as soon as the right sizeis reached, the pattern is lowered to and rests on the platform 51,which pushes the shaft 52a down, moves the lug 68 to depress pushbutton67' and actuates the switch 67. This actuates the lens drive mechanism,rotating the lens until the pattern is again elevated above platform 51,whereupon shaft 520 rises, carrying lug 68 with it, the pushbutton 67'rises, and the switch 67 shuts off the lens drive mechanism. The lens isheld stationary until that part is ground down to size, and the cyclethen is repeated.

The lens drive mechanism is as follows. Fitted to the like sprocketwheels 40 on each shaft 21, 22 are like loop chain drives 75, which attheir other end loop over sprocket wheels 76. The wheels 76 are fixedlymounted to shaft 77, which rotates on ball bearings 78 fitted in thelens head housing 79. The shaft 73 extends between side walls 13, 14' ofmovable carriage 90. The shaft ends extend through the side walls 13, 14on each side, and the side walls are fixed ball bearings 77a on whichthe shaft 77 pivots. On the projecting portion at side wall 14" ismounted another sprocket wheel 82 and loop chain drive 83 extending tothe main drive sprocket wheel 84 on the drive shaft 80 of an electricmotor 81. The chain 83 thus constitutes the primary chain, and thechains 75, the secondary chains, of the lens drive mechanism. Operationof the motor 81 rotates the drive shaft 80, and with it the primary andsecondary chains, for corresponding rotation of the lenscarrying shafts21 and 22 during the grinding operation, as controlled by microswitch67.

The motor 81 is fixedly mounted on the side wall 14' of the movablecarriage 90. The electrical equipment for control of the motor includingthe switches 87,87 controlling the operation thereof are mounted on thebridge 94 which extends between the side walls 13', 14', over the motor.The switches 86, 87 have their controls on the top of the bridge, foreasy access to the operator of the machine, as well as to keep wiringaway from coolant spray. An electric line 85 is attached to the mainpower supply of the building in which the machine is installed. Themanually operated main switch 86 in this line controls the supply ofelectric current to the motor. The switch is normally on duringoperation of the machine, but it can be turned off when the machine isno longer in use.

The supply of current to the motor even when switch 86 is on isnonetheless controlled secondarily by a microswitch 87, which isarranged to be normally in the on position, but is held in the offposition by the cam segment 113 of the master cam 20, which contacts theswitch pushbutton 87' only when the master cam is at the end of a cycle.Thus, in normal operation, the machine is always turned offautomatically when the master cam 20 has reached the end of a grinding,finishing and beveling cycle. A pushbutton 121 shorts out switch 87, andturns the current on (when switch 86 is on), to start the motor 81whereupon cam 20 moves segment 113 out of contact with switch pushbutton87', and the current then remains on for the remainder of the cycle.

While switches 86 and 87 are on, the motor 135 is in continuousoperation, for continuous operation of the grinding wheel and bevelingwheel 71. These are driven on shaft 105, on which they are fixed forrotation therewith, by way of the grooved pulley wheel 108, loop belt109, and grooved pulley wheel 118, attached to drive shaft 134 of themotor 135. However, as noted above, rotation of shafts 21, 22 isintermittent, controlled by switch 67, on shaft 520.

If a pump 130 is provided to pump coolant spray to the lens duringgrinding, this can also be connected in the same electrical circuit, sothat the pump is always in operation while the grinding wheel andbeveling wheel are in operation, but are turned off automatically whenthese are turned off.

The master cam 20 is mounted for rotation on one end of camshaft 85,which is supported at the rear side of plates 13 and 14 of the movablecarriage, on ball bearings a which are fixed in the plates 13', 14'. Onthe stub end 95 of camshaft 85 projecting from side wall 14' is mounteda toothed drive gear 88, which meshes with and is driven by acorresponding main drive gear 89 attached to the motor drive shaft 80,together with the main drive sprocket wheel 84. Thus, operation of themotor rotates the gear 89 and with it the gear 88 and camshaft 85, andthus the master cam 20.

The beveling pressure control is arranged for actuation by section 111of the master cam 20, and comprises a cam follower 97, a weight 98 and athrust point 99, carried on arms 100, 101., 102, extending f mm thepivotally mounted support base 107. The support base 107 pivots on thepivot pin 103, which is attached to the movable carriage 90. The weightis slidably held on a weight support shaft 104, which is fixed at oneend of the arm 102. The thrust point 99 bears against the upright arm93, when the beveling pressure control is actuated, tending to thrustcarriage 90 to the right, its shaft 91, 92 moving sideways alongbushings 18, under the pivoting force of weight 98, but it can reachthis position only when permitted to do so by the surface configurationof the master cam section 111 on which the cam follower 97 travels.

In the normal non-actuating position, the cam surface 111 holds the camfollower 97 down, so that the weight 98 is raised, and the thrust point99 is held away from the plate upright arm 93. The pressure control as-'sembly is held in this position throughout all of the grinding cycle,except when the lens is in contact with the beveling wheel. When thisportion of the cycle is reached, the pressure control assembly isbrought to an actuating position. The surface of the cam section 111 onwhich the cam follower 97 travels is depressed at this moment,permitting the cam follower97 to rise, and the pressure control support107 to pivot, to the right, until the thrust point 99 is brought incontact with the upright arm 93, at which point it can move no further.Since the pivot pin 103 is carried on the movable carriage 90, the forceexerted by the weight 98 on arm 93 now thrusts the carriage towards theright, thus increasing the pressure contact of the lens with thelefthand taper of the beveling wheel, tending to bevel the lens more onthe right side than on the left. The amount of pressure can becontrolled by the leverage of the weight, determined by the weight andby the position of the weight on the arm support 102. The weight can bemoved along shaft 104 as desired, and locked in the desired position bymeans of the set screw 106. In this way, any desired amount of pressurecan be applied to the lens during beveling.

The master cam 20 has a complex four-component surface configuration,which makes it possible to control via the four cam followers all of thesequential grinding steps of the machine, in a given lens grinding andfinishing and beveling cycle. A single rotation of the master camcorresponds to a single cycle.

As best seen in FIGS. 1, 2, 3, and 8, the master cam is composed of fourcam sections l) a lift and drop control section 110 for pivoting thelens-carrying head housing 5 and associated parts; (2) a bevel controlcam section 111; (3) a moveable carriage control cam section 112; and(4) a switch control cam segment 113.

The bevel control cam section 111 comprises a cylinder segment in whichthe cut-out portion 114 corresponds to the desired actuation period forthe beveling pressure control assembly, whose cam follower 97 movesalong this portion. When the cam follower reaches the cut-out portion114, the assembly is permitted to pivot to the right, and the thrustpoint 99 is brought against the upright arm 93, applying asideways-moving force to the moveable carriage 90.

- The lift and drop section 110 comprises a cylinder segment in whichthere is a portion 1 15 of intermediate diameter, a cut-out portion 116,and a projecting portion 117. The portion 115 corresponds to that partof the cycle where the lens is in contact with the flat grinding wheel.The cut-out portion 116 corresponds to the portion of the cycle wherethe lens is in contact with the beveling wheel, which is lower than thegrinding wheel. The projecting portion 117 corresponds to the lifting ofthe lens-carrying head 5 at the conclusion of the beveling cycle.

The cam follower end 119 of the pivotable platform support arm 53travels on the cam section 110. When the end 119 moves off the portion117 to portion 115, the head 5 is lowered until the lens can contact thegrinding wheel. Grinding continues with intermittent lens rotation,controlled by switch 67 to occur only when the pattern contacts theplatform 51. When grinding is complete, the end 119 moves onto portion116, and the head 5 lifts slightly, and then is lowered further, tocontact the beveling wheel. When the end 119 moves onto portion 117, theplatform-supporting end 120 lifts, carrying with it the pattern restingon the platform 51 and shaft 21 to which it is attached, thus liftingthe lens-carrying head 5, ending the beveling operation.

The carriage control section 112 of the cam 20 controls the relativetransverse position of the carriage 90 with respect to the grindingwheel.

A groove 120 extends all around the surface of this section of the cam.Cam follower 96 attached to upright 93 rides in the groove, which thusis a cam track. The upright 93 has a slot 125 across the top end, inwhich is slidably fitted a plate 123 to which the cam follower 96 isaffixed. The plate 123 and cam follower 96 can be held in any positionin the slot by set screws 124,

which allow a small adjustment of the plate towards the center or sideof the slot. The upright 93 can be rotated, and is held against rotationby set screw 93a. Such rotation together with the position of the platein the slot provides a considerable adjustment of the position of thecam follower 96 so that it will track properly along the side of the camtrack 120.

The upright 93 is rotatably attached to the base 1, while the master camis attached via camshaft to the movable carriage 90, so that the courseof the groove 120 along the surface of master cam 20 determines thetransverse position of the carriage 90. Thus, the groove 120 of camsection 112 guides the floating carriage and the lens-holding lens head5 transversely, to position it precisely with respect to the grindingand bevel ing wheels at each stage of the grinding and beveling cycle.It is also possible to fix the master cam 20 to the base, and the camfollower 96 to the movable carriage, but this requires that the othercam followers mounted on the carriage be slidable with respect thereto,and fixed against transverse movement to the base with the master cam,which is a more cumbersome arrangement.

The cam track at the start of the cycle is just the size of follower 96,so that it fixes the carriage in a transverse position, and positionsthe carriage 90 so that the lens holders of head 5 hold the lensdirectly opposite the grinding wheel 70. Then, at the conclusion of thisoperation, the cam track 120 describes a lefthand S curve, and guidesthe floating carriage 90 transversely so as to put the lens opposite thefinishing and beveling wheel 71. At this stage, beyond the S curve, thegroove 120 in the cam widens, so that the follower 96 is no longerfixedly held in a transverse position with respect to the beveling wheel71. Therefore, the carriage 90, the head 5 and the lens can floatfreely, as controlled by the contour of the lens edge in the groove ofthe beveling wheel. During this portion of the cycle, the bevellingpressure control is operative, as stated above, to prepare an off centerbevel.

At the end of the beveling cycle, the groove 120 narrows again to thewidth of the cam follower 96 so as to once more fix the carriage 90 in atransverse position,

beveling cycle. At all other positions of the cam 20, switch 87 is on.

In operation, the main control switch 86 is turned on, and the machineis then ready to start. However, the motor 81 is not yet on, because thepush-button switch 87 is in the off position, held there by cam segment113 of the master cam 20. The lens holder control hand wheel 49 isrotated to loosen it, and the shaft 22 thereby pulled to the right,separating the lens holder segments 27, 28. The lens is then put inplace between the two lens holder segments 27, 28. The lens holdersegment 27 is removed, the lens blank fitted convexside in, against theconcavity, with its optical center at the central axis thereof. The lensholder segment is carefully fitted back in the chuck 270 on pins 27b,using a lens clamp of conventional type, and the control hand wheel 49then rotated in the opposite direction, so as to lock the lens betweenthe two holder portions, by moving shaft 22 and segment 28 to the left,and tightening it down, and firmly gripping the lens therebetween forthe grinding operation.

A pattern or template 122 is placed on the end 50 of the shaft 21, andthe sizing dial 62 turned by knob 63 to and locked in the proper sizesetting for the lens to be ground from the blank. This raises theplatform 51 to the correct height. The machine is then ready to operate.

Now, the pushbutton 121 is depressed, shorting out switch 87, startingthe motor 81, as well as pump 130, and starting rotation of the mastercam 20, as well as the grinding and beveling wheels 70, 71. Rotation ofthe master cam moves cam section 110 into the portion 115, to lower thehead 5, and brings the lens into contact with the grinding wheel 70. Thelens is oversize, and holds template 122 above the platform 51. Hence,the platform is not depressed, so that lug 68 does not actuate switch67, and the shafts 21, 22 are stationary, and held so by the stationarydrive mechanism, sprocket wheels 40, chains 75. The lens is ground downrather quickly, and eventually the template 122 comes into contact withthe platfonn S1, depresses it sufficiently to actuate the switch 67, andthen shafts 21, 22 and the lens are rotated to a new lens position,since the lens is oversize there. This results in again lifting thetemplate, and halting the rotation. Grinding continues in this way, withintermittent rotation, until one complete rotation of the lens has beeneffected, and the lens conforms in size and shape to the desiredpattern. Thus, the lens blank is held firmly against the grinding wheeland does not rotate until it has been ground down to the desired size,reflected in the position of the pattern on the platform. After the lenshas reached the desired size, the cam follower 96 reaches the first Scurve in the groove 120, as well as an elevator in periphery of a cam.This lifts the lens away from the wheels, and completes the initialgrinding operation.

The cam follower 96 traveling in the groove 120 on the master cam nowtravels the S curve, by which it is deflected to the left, carrying withit the carriage 90 and the lens-carrying head 5, to a position over thebeveling and finishing wheel 71. Since the cam follower end of supportarm 53 has traveled the course of portion 115, and has reached the nextportion 116 of the cam, the arm 53 is lifted a little (to allow sidewaysmovement of the carriage) and then lowered to a lower position, carryingwith it the platform 51, pattern 122 and the lens-carrying head 5, sothat the lens is moved down to the beveling wheel 71. The pattern 122rests on the platform, since the lens has been cut to size, so switch 67is on and shafts 21, 22 rotate, while the rough-edged lens blank is inengagement with the beveling wheel 71. The cam follower 96 controllingthe transverse movement of the carriage now enters the wide portion ofthe groove 120, where sidewise movement of the cam follower 96 is nolonger restricted, thus setting the lens blank free to move sidewise, incontact with the beveling wheel.

However, the freedom of the lens to do so is not wholly uncontrolled, ifan off-center bevel is desired, for the bevel control cam section 111now puts the bevel pressure control in operation, and the weight 98exerts a rightwardly-directed sidewise force on the carriage 90 and thustends to drive the lens toward the right, during the beveling operation.Of course, use of the beveling control is optional; on thin lenses, anoffcenter bevel may not be desired, for example. In this event, theweight 98 is removed, so that the bevel control is ineffective. It isnot necessary to inactivate the cam.

As the master cam 20 continues to turn, the beveling is completed, andthe cam follower 97 of the beveling pressure control pivot shaft 99reaches the end of portion 114, and enters the normal diameter portionof this section, and is moved downwardly, so that thrust point 99 ismoved away from upright 93, and the pressure is released. At the sametime, the cam follower 96 traveling in the groove on the master camreaches the narrow portion of the groove, and travels the returning Scurve, so that it moves the carriage 90 to the right, at the same timeas the support arm 53 has reached the cam portion 1 17 and is moveddownwardly, thus lifting the platform 51 and the lens-carrying head 5,so that the lens is brought away from contact with the beveling wheel,and the carriage is returned to its original position, when the lens isdirectly over the grinding wheel 70. The master cam 20 has now completedone full revolution, and the cycle is complete. The raised cam seg ment113 on the master cam comes in contact with the pushbutton 87 of themicroswitch 87, turning off the current, and shutting off the motor 81,so that the machine stops. The lens is always at the same angle ofrotation at the end, so that a new lens may be inserted easily. Thecontrol dial 49 can now be loosened, and the finished lens removed.After insertion of a new blank, another cycle can be begun by depressingthe pushbutton 121, which starts a new cycle.

The pushbutton switch 121 permits current to flow only while it isdepressed, and therefore it must be held depressed for a long enoughtime for the main cam 20 to move so that the raised portion 113 comesaway from contact with the button 87' of microswitch 87, thus permittingthe button to rise and the switch to close, and current to continue forthe remainder of the cycle. This is a fail-safe feature. If at any timethe machine has to be stopped, in the course of a cycle, this can bedone by turning off the main control switch 86, which is readily andquickly reached by theoperator on bridge 94.

The machine of the invention also includes as an optional but preferredfeature means for applying fluid such as a coolant liquid to the lenssurface during the grinding, beveling and finishing, to facilitate theseoperations. A pump motor is provided, on the platform or table on whichthe base 1 is supported. A tank reservoir 131 is connected in serieswith a line 132 leading directly to a point just above a lens inposition between the lens holders 27, 28, and the pump feeds a stream ofcoolant fluid from the reservoir 131 via this line to the lens, in arecirculating fashion. A drain 133 at the bottom of tank 6 is provided,for permitting the coolant fluid to release to pump reservoir.

Operation of the pump 130 is controlled by the microswitch 86 on themaster cam 20, so that fluid is continuously supplied to the lens whilethe lens is being ground, bevelled and finished, and when the cycle ofthe machine reaches its conclusion, and power is shut off, the pump 130is also shut off.

Any type of coolant liquid can be used, such as aqueous solutions of apolyol, such as ethylene glycol, propylene glycol, or glycerol.

Having regard to the foregoing disclosures, the following is claimed asthe inventive and patentable em bodiments thereof:

1. In a lens edge-grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, and a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, and the rotating, pivoting andreciprocating movement of the lens blank holder, the improvement whichcomprises a single master cam having a plurality of cam surfaces andassociated cam followers in operative engagement therewith, whichestablish and control each of the various steps of the grinding andbeveling and finishing operation, one cam surface effecting pivotalmovement of a lens-blank holder and lens towards and away from thegrinding wheel, and pivotal movement of the lens carrying head and lenstowards and away from the beveling and finishing wheel; a second camsurface effecting transverse or sideways movement of a lens blank holderfrom opposite the grinding wheel to opposite the beveling and finishingwheel, and back, while holding the lens blank holder against transverseor sideways movement during the grinding, and allowing such movementduring the beveling and finishing; and a third cam surface adapted tomove into operative relation to an electric switch effecting a shutoffof the electric circuit at the end of a grinding and beveling andfinishing cycle.

2. A machine according to claim 1 including a pattern cam rotatable withthe lens blank holder controlling lens shape and size, a pattern camplatform on which the pattern cam rotates, and a rotatable spiral camcontrolling the position of the platform to locate the pattern cam for aselected lens size.

3. A machine according to claim 2, including a locking means fixing thespiral cam against rotation and preventing the platform from moving intoa different size position during use.

4. A machine according to claim I, in which the lens blank holder ispivotably mounted on and movable with a reciprocable carrier, oneportion of the master cam controlling reciprocation of the carrier, andanother portion controlling pivoting of the lens blank holder.

5. A machine according to claim 1, including beveling pressure controlmeans in operative connection with the lens blank holder for applyingpressure to the lens blank to move it sideways while it is in operativeengagement with the beveling and finishing wheel, to displace the bevelcenter in any desired direction.

6. A machine according to claim 1, including a lens holder in twosegments, one presenting a concave and one presenting a convex surfaceto a lens blank held therebetween, and a resilient friction pad attachedto each of said surfaces that can hold a curved lens blank at itsoptical center throughout the grinding, beveling and finishingoperations, without lens breakage or slippage.

7. A machine according to claim 1, comprising an electric motor drivingsaid wheels; an electric motor driving the rotating, pivoting andreciprocating movement of the lens blank holder and pattern cam; eachmotor being operatively connected thereto by an electrical circuit thatcontrols operation of the motors during a grinding, beveling andfinishing cycle on a failsafe basis, with an automatic shut-off of eachmotor at the end of the cycle.

8. A machine according to claim 1, including a base; at least twoapertured supports fixed on the base; at least two shafts extendingthrough the support apertures; and a movable carriage supported on theshafts and slidable transversely with respect to the supports, suchtransverse movement thereof being controlled by the master cam, thecarriage carrying a lens head housing within which the lens blank holderis disposed.

9. A machine according to claim 8, in which the shafts are fixed to thecarriage and the support apertures carry ball bushings which allow freemovement of the shafts sideways with respect to the supports but preventrotation of the carriage about the supports.

10. A machine according to claim 8, having a lens head housing pivotablymounted on a shaft which is supported on the movable carriage.

11. A machine according to claim 10,- in which the lens head housing hasa hinged lens cover enclosing the lens holder and any lens held therein,the hinged cover providing access to the lens holder for insertion andre-. moval of a lens therein.

12. A machine according to claim 1, having a tank receiving sedimentground off a lens blank, the tank having a door which gives access tothe interior of the tank for cleaning purposes, the apertured supportsbeing fixed to the tank, and the lens blank holder being disposed overthe tank.

13. A machine according to claim 1, including a fourth cam surfacecontrolling application of and removal of pressure to the lens duringthe beveling and finishing, so as to control the beveling eccentricity.

14. A machine according to claim 13, in which the fourth cam follower isoperatively connected to a pivotable pressure-applying beveling controlmeans, to pivot it into and out of a pressure-applying position withrespect to a lens blank in the lens blank holder, but only while thelens blank is in contact with the beveling and finishing wheel.

15. A machine according to claim I, in which the master-cam is in theform of a cylinder having adjacent cam sections bearing the first,second and third cam surfaces.

16. A machine according to claim '1, in which the master cam is mountedon a motor-driven camshaft,

and the motor rotates the camshaft and the lens blank holder in asynchronized operation.

17. A machine according to claim 1, in which the first cam follower isoperatively connected to the lens blank holder and pivots it about anaxis parallel to the axis of rotation of the lens, and the first camsurface is of the hill-and-dale type, and raises or lowers the camfollower to effect the pivoting movement.

18. A machine according to claim 1, in which one of the second camfollower or the master cam is operatively connected to a movablecarriage on which the lens blank holder is mounted, and actuatestransverse reciprocating movement thereof, first in one direction, andthen back, between limiting positions corresponding to positions of thelens opposite the grinding wheel and the beveling and finishing wheel,respectively.

19. A machine according to claim 17, in which the second cam surface isprovided with a groove in which the second cam follower travels, oneportion of the groove having a width to accommodate the cam follower,and to hold the movable carriage on which the lens carrying head ismounted in a fixed transverse position while the lens is in contact withthe grinding wheel during the grinding portion of the cycle, and anotherportion having a width to permit free transverse movement of the movablecarriage while the lens is in contact with the beveling and finishingwheel, during the beveling and finishing portion of the cycle.

20. A machine according to claim 1, in which the third cam surface is asmall segment holding a pressureoperated button of the electric switchin an off position while in contact therewith, and in all otherpositions allowing the button to remain in an on position.

21. In a lens-edge grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, a pattern or template platformcontrolling lens size according to its position with respect to theperipheral surface of the grinding, beveling and finishing wheels, and apattern cam rotatable with the lens blank holder controlling lens shapeand size, the improvement which comprises, in combination, a spiral camfor adjusting the position of the platform with respect to theperipheral surface of the grinding, beveling and finishing wheels,comprising a cam wheel mounted on and rotatable about a fixed axis witha camshaft, and having a spiral cam slot rising helically in a uniformcurve from a central part of the wheel to its surface, and a camfollower fixedly attached to the platform, and travelling in the spiralcam slot, moving the platform reciprocably according to its position inthe slot, and the position of the cam wheel; and a lens size controlmechanism in operative connection with the spiral cam, and rotatabletherewith, including a cam lock which is axially mounted over and doesnot rotate with the camshaft, and locking means operatively connected toand rotatable with the camshaft and reciprocably movable into and awayfrom fixedly interlocking engagement with the cam lock at any of aplurality of fixed positions corresponding to lens size gradations sothat the position of the spiral cam is fixed when said locking means isinterlocked with the cam lock, and the spiral cam cannot be rotated; andbiasing means to keep said means normally in interlocking engagementwith the cam lock.

22. A machine according to claim 21, comprising a vertical shaft onwhich the platform is mounted; and a pivotable support arm having anaperture in which the shaft is slidably held, the top end of the shaftbeing fixed to the platform, and the bottom end of the shaft carrying acylindrical ball-bearing which serves as the cam follower.

23. A machine according to claim 22, in which the camshaft extendsthrough and rotates in an aperture of the support arm, a peripherallytoothed cam lock is fixed to the support arm, and having a centralaperture through which the camshaft extends, the camshaft beyond thelock having a polygonal configuration, and supporting a sizing dial anda sizing knob slidably attached to the end of the shaft, and rotatablemanually to rotate the shaft, and always having the same radial positionas the spiral cam, so that their position reflects exactly the positionof the spiral cam, and therefore of the platform.

24. A machine according to claim 23, in which the sizing dial has aninternal recess conforming to the external configuration of andreceiving the cam lock, and the sizing dial and knob can be slid alongthe shaft so that the dial moves into and out from engagement with thecam lock, such movement being controlled by the sizing knob, with pinsdisposed in spaced positions along the interior wall of the recess ofthe sizing dial to mesh with the teeth of the cam lock, and lock thecamshaft against rotation.

25. A machine according to claim 22, having an electric motor to rotatethe lens holders; a switch operatively connected to the motor andattached to the support arm, with a switch control means extendingoutwardly therefrom; a lug on the shaft positioned to depress thecontrol means and actuate an electric circuit; the shaft being movablewith respect to the support arm, to move the lug and depress the controlmeans whenever a lens pattern is resting on the platform, so that theswitch is on and the lens holders rotated only when a lens blank hasbeen cut down to a size such that the pattern rests on the platform.

26. In a lens edge-grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, and a lens blank holder in twosegments holding the lens blank in operative relation to the said wheelsfor grinding, beveling and finishing thereof to a size and pattern, theimprovement which comprises two lens holder shafts in axially end-facingrelationship, each facing end having a lens holder segment attachedthereto; drive means for rotating each shaft, and at least one of theshafts being movable axially transversely with respect to the other, andbeing slidably supported in a rotatable sleeve, the movable shaft beingsupported within a housing and having a control means attached over itsother end, the control means having a socket in which the shaft end isinserted; a thrust bearing in the socket and disposed over the shaftend; an externally threaded tubular shaft enclosing the said end of themovable shaft and attached at one end to the control means, for rotationtherewith over the movable shaft; a threaded socket in the housing intowhich the tubular shaft threads; and retaining means affixed to themovable shaft end within the socket of the control means and retainingit within the socket for movement with the control means upon relativemovement of the tubular shaft within the socket.

27. A machine according to claim 26, in which the two shafts arerotatably supported in the central apertures of two pairs ofball-bearing wheels.

28. A machine according to claim 26, in which the drive means for theshafts and/or sleeve are sprocket wheels attached thereto and driven bychain drives.

29. In a lens edge-grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size pattem,'and a pattem'or template platform controllinglens size according to its position with respect to the peripheralsurface of the grinding, beveling and finishing wheels, the improvementwhich comprises a lens size control mechanism in operative connectionwith the platform, to raise or lower the platform, including a rotatablesizing dial mounted on a shaft, rotation of which raises or lowers theplatform, a lock axially and fixedly held over the shaft so as not torotate therewith, and locking means fixedly interlocking with the lockat any of a plurality of fixed positions corresponding to lens sizegradation and holding the dial and shaft against rotation when sointerlocked.

30. A machine according to claim 29, including means to bias the dialand locking means into locking engagement with the lock.

31. A machine according to claim 29, in which the lock comprises atoothed gear, and the locking means is adapted to mesh with teeth on thegear.

32. In a lens edge-grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, and a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, the improvement which comprises abeveling pressure control for imposing an off-center bevel to a lensedge, comprising a weight and a thrust point carried on arms spaced onopposed sides of and extending from a support pivotally mounted inoperative connection with the lens blank holder, the thrust point beingadapted to bear against a fixed base and thrust the lens blank holdersideways under the pivoting force of the weight, to impart a side-'ways-applied beveling pressure to a lens blank against one side of thebeveling and finishing wheel.

33. A machine according to claim 32, in which the weight is slidablyheld on a shaft to adjust the bearing pressure of the thrust pointagainst the base.

34. A machine according to claim 32, arranged to be cam-actuated,comprising a cam surface; and a cam follower attached to an armextending from the support; the cam surface normally holding the camfollower so that the thrust point is held away from the fixed base, butwhen a lens is in contact with the bevel ing wheel permitting the camfollower to pivot the pressure control support until the thrust point isbrought in contact with the fixed base.

35. In a lens edge-grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, and a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, the improvement which comprises a base;at least two apertured supports fixed on the base; at least one shaftextending through the apertures between the supports; and a movablecarriage attached to the shaft, which is arranged for reciprocabletransverse movement with respect to the supports in the apertures, andcarrying the lens blank holder for pivotal movement thereof towards andaway from the grinding wheel, and towards and away from the beveling andfinishing wheel, the carriage carrying a cam movable by a cam followerfixed to the base, for effecting and controlling reciprocable movementof the carriage and the shaft with respect to the grinding and bevelingand finishing wheels, and the cam having a circumferential groove inwhich the cam follower travels.

36. A machine according to claim 35, having two parallel shaftsextending between and sliding transversely through the apertures of thesupports.

37. A machine according to claim 36, in which the shafts are supportedon ball bushings disposed in the support apertures allowing reciprocablemovement but not pivoting movement thereof.

1. In a lens edge-grinding and finishing machine having lensedgegrinding, beveling and finishing wheels, and a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, and the rotating, pivoting andreciprocating movement of the lens blank holder, the improvement whichcomprises a single master cam having a plurality of cam surfaces andassociated cam followers in operative engagement therewith, whichestablish and control each of the various steps of the grinding andbeveling and finishing operation, one cam surface effecting pivotalmovement of a lens-blank holder and lens towards and away from thegrinding wheel, and pivotal movement of the lens carrying head and lenstowards and away from the beveling and finishing wheel; a second camsurface effecting transverse or sideways movement of a lens blank holderfrom opposite the grinding wheel to opposite the beveling and finishingwheel, and back, while holding the lens blank holder against transverseor sideways movement during the grinding, and allowing such movemEntduring the beveling and finishing; and a third cam surface adapted tomove into operative relation to an electric switch effecting a shut-offof the electric circuit at the end of a grinding and beveling andfinishing cycle.
 2. A machine according to claim 1 including a patterncam rotatable with the lens blank holder controlling lens shape andsize, a pattern cam platform on which the pattern cam rotates, and arotatable spiral cam controlling the position of the platform to locatethe pattern cam for a selected lens size.
 3. A machine according toclaim 2, including a locking means fixing the spiral cam againstrotation and preventing the platform from moving into a different sizeposition during use.
 4. A machine according to claim 1, in which thelens blank holder is pivotably mounted on and movable with areciprocable carrier, one portion of the master cam controllingreciprocation of the carrier, and another portion controlling pivotingof the lens blank holder.
 5. A machine according to claim 1, includingbeveling pressure control means in operative connection with the lensblank holder for applying pressure to the lens blank to move it sidewayswhile it is in operative engagement with the beveling and finishingwheel, to displace the bevel center in any desired direction.
 6. Amachine according to claim 1, including a lens holder in two segments,one presenting a concave and one presenting a convex surface to a lensblank held therebetween, and a resilient friction pad attached to eachof said surfaces that can hold a curved lens blank at its optical centerthroughout the grinding, beveling and finishing operations, without lensbreakage or slippage.
 7. A machine according to claim 1, comprising anelectric motor driving said wheels; an electric motor driving therotating, pivoting and reciprocating movement of the lens blank holderand pattern cam; each motor being operatively connected thereto by anelectrical circuit that controls operation of the motors during agrinding, beveling and finishing cycle on a fail-safe basis, with anautomatic shut-off of each motor at the end of the cycle.
 8. A machineaccording to claim 1, including a base; at least two apertured supportsfixed on the base; at least two shafts extending through the supportapertures; and a movable carriage supported on the shafts and slidabletransversely with respect to the supports, such transverse movementthereof being controlled by the master cam, the carriage carrying a lenshead housing within which the lens blank holder is disposed.
 9. Amachine according to claim 8, in which the shafts are fixed to thecarriage and the support apertures carry ball bushings which allow freemovement of the shafts sideways with respect to the supports but preventrotation of the carriage about the supports.
 10. A machine according toclaim 8, having a lens head housing pivotably mounted on a shaft whichis supported on the movable carriage.
 11. A machine according to claim10, in which the lens head housing has a hinged lens cover enclosing thelens holder and any lens held therein, the hinged cover providing accessto the lens holder for insertion and removal of a lens therein.
 12. Amachine according to claim 1, having a tank receiving sediment groundoff a lens blank, the tank having a door which gives access to theinterior of the tank for cleaning purposes, the apertured supports beingfixed to the tank, and the lens blank holder being disposed over thetank.
 13. A machine according to claim 1, including a fourth cam surfacecontrolling application of and removal of pressure to the lens duringthe beveling and finishing, so as to control the beveling eccentricity.14. A machine according to claim 13, in which the fourth cam follower isoperatively connected to a pivotable pressure-applying beveling controlmeans, to pivot it into and out of a pressure-applying position withrespect to a lens blank in the lens blank holder, but only while thelens blank is in coNtact with the beveling and finishing wheel.
 15. Amachine according to claim 1, in which the master cam is in the form ofa cylinder having adjacent cam sections bearing the first, second andthird cam surfaces.
 16. A machine according to claim 1, in which themaster cam is mounted on a motor-driven camshaft, and the motor rotatesthe camshaft and the lens blank holder in a synchronized operation. 17.A machine according to claim 1, in which the first cam follower isoperatively connected to the lens blank holder and pivots it about anaxis parallel to the axis of rotation of the lens, and the first camsurface is of the hill-and-dale type, and raises or lowers the camfollower to effect the pivoting movement.
 18. A machine according toclaim 1, in which one of the second cam follower or the master cam isoperatively connected to a movable carriage on which the lens blankholder is mounted, and actuates transverse reciprocating movementthereof, first in one direction, and then back, between limitingpositions corresponding to positions of the lens opposite the grindingwheel and the beveling and finishing wheel, respectively.
 19. A machineaccording to claim 17, in which the second cam surface is provided witha groove in which the second cam follower travels, one portion of thegroove having a width to accommodate the cam follower, and to hold themovable carriage on which the lens carrying head is mounted in a fixedtransverse position while the lens is in contact with the grinding wheelduring the grinding portion of the cycle, and another portion having awidth to permit free transverse movement of the movable carriage whilethe lens is in contact with the beveling and finishing wheel, during thebeveling and finishing portion of the cycle.
 20. A machine according toclaim 1, in which the third cam surface is a small segment holding apressure-operated button of the electric switch in an ''''off''''position while in contact therewith, and in all other positions allowingthe button to remain in an ''''on'''' position.
 21. In a lens-edgegrinding and finishing machine having lens-edge grinding, beveling andfinishing wheels, a rotatable, pivotable and reciprocable lens blankholder holding the lens blank in operative relation to the said wheelsfor grinding, beveling and finishing thereof, to a size and pattern, apattern or template platform controlling lens size according to itsposition with respect to the peripheral surface of the grinding,beveling and finishing wheels, and a pattern cam rotatable with the lensblank holder controlling lens shape and size, the improvement whichcomprises, in combination, a spiral cam for adjusting the position ofthe platform with respect to the peripheral surface of the grinding,beveling and finishing wheels, comprising a cam wheel mounted on androtatable about a fixed axis with a camshaft, and having a spiral camslot rising helically in a uniform curve from a central part of thewheel to its surface, and a cam follower fixedly attached to theplatform, and travelling in the spiral cam slot, moving the platformreciprocably according to its position in the slot, and the position ofthe cam wheel; and a lens size control mechanism in operative connectionwith the spiral cam, and rotatable therewith, including a cam lock whichis axially mounted over and does not rotate with the camshaft, andlocking means operatively connected to and rotatable with the camshaftand reciprocably movable into and away from fixedly interlockingengagement with the cam lock at any of a plurality of fixed positionscorresponding to lens size gradations so that the position of the spiralcam is fixed when said locking means is interlocked with the cam lock,and the spiral cam cannot be rotated; and biasing means to keep saidmeans normally in interlocking engagement with the cam lock.
 22. Amachine according to claim 21, comprising a vertical shaft on which theplatform is mounted; and a pivotable support arm having an aperture iNwhich the shaft is slidably held, the top end of the shaft being fixedto the platform, and the bottom end of the shaft carrying a cylindricalball-bearing which serves as the cam follower.
 23. A machine accordingto claim 22, in which the camshaft extends through and rotates in anaperture of the support arm, a peripherally toothed cam lock is fixed tothe support arm, and having a central aperture through which thecamshaft extends, the camshaft beyond the lock having a polygonalconfiguration, and supporting a sizing dial and a sizing knob slidablyattached to the end of the shaft, and rotatable manually to rotate theshaft, and always having the same radial position as the spiral cam, sothat their position reflects exactly the position of the spiral cam, andtherefore of the platform.
 24. A machine according to claim 23, in whichthe sizing dial has an internal recess conforming to the externalconfiguration of and receiving the cam lock, and the sizing dial andknob can be slid along the shaft so that the dial moves into and outfrom engagement with the cam lock, such movement being controlled by thesizing knob, with pins disposed in spaced positions along the interiorwall of the recess of the sizing dial to mesh with the teeth of the camlock, and lock the camshaft against rotation.
 25. A machine according toclaim 22, having an electric motor to rotate the lens holders; a switchoperatively connected to the motor and attached to the support arm, witha switch control means extending outwardly therefrom; a lug on the shaftpositioned to depress the control means and actuate an electric circuit;the shaft being movable with respect to the support arm, to move the lugand depress the control means whenever a lens pattern is resting on theplatform, so that the switch is on and the lens holders rotated onlywhen a lens blank has been cut down to a size such that the patternrests on the platform.
 26. In a lens edge-grinding and finishing machinehaving lens-edge grinding, beveling and finishing wheels, and a lensblank holder in two segments holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishing thereofto a size and pattern, the improvement which comprises two lens holdershafts in axially end-facing relationship, each facing end having a lensholder segment attached thereto; drive means for rotating each shaft,and at least one of the shafts being movable axially transversely withrespect to the other, and being slidably supported in a rotatablesleeve, the movable shaft being supported within a housing and having acontrol means attached over its other end, the control means having asocket in which the shaft end is inserted; a thrust bearing in thesocket and disposed over the shaft end; an externally threaded tubularshaft enclosing the said end of the movable shaft and attached at oneend to the control means, for rotation therewith over the movable shaft;a threaded socket in the housing into which the tubular shaft threads;and retaining means affixed to the movable shaft end within the socketof the control means and retaining it within the socket for movementwith the control means upon relative movement of the tubular shaftwithin the socket.
 27. A machine according to claim 26, in which the twoshafts are rotatably supported in the central apertures of two pairs ofball-bearing wheels.
 28. A machine according to claim 26, in which thedrive means for the shafts and/or sleeve are sprocket wheels attachedthereto and driven by chain drives.
 29. In a lens edge-grinding andfinishing machine having lens-edge grinding, beveling and finishingwheels, a rotatable, pivotable and reciprocable lens blank holderholding the lens blank in operative relation to the said wheels forgrinding, beveling and finishing thereof, to a size pattern, and apattern or template platform controlling lens size according to itsposition with respect to the peripheral surface of the grinding,beveling and finisHing wheels, the improvement which comprises a lenssize control mechanism in operative connection with the platform, toraise or lower the platform, including a rotatable sizing dial mountedon a shaft, rotation of which raises or lowers the platform, a lockaxially and fixedly held over the shaft so as not to rotate therewith,and locking means fixedly interlocking with the lock at any of aplurality of fixed positions corresponding to lens size gradation andholding the dial and shaft against rotation when so interlocked.
 30. Amachine according to claim 29, including means to bias the dial andlocking means into locking engagement with the lock.
 31. A machineaccording to claim 29, in which the lock comprises a toothed gear, andthe locking means is adapted to mesh with teeth on the gear.
 32. In alens edge-grinding and finishing machine having lens-edge grinding,beveling and finishing wheels, and a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, the improvement which comprises abeveling pressure control for imposing an off-center bevel to a lensedge, comprising a weight and a thrust point carried on arms spaced onopposed sides of and extending from a support pivotally mounted inoperative connection with the lens blank holder, the thrust point beingadapted to bear against a fixed base and thrust the lens blank holdersideways under the pivoting force of the weight, to impart asideways-applied beveling pressure to a lens blank against one side ofthe beveling and finishing wheel.
 33. A machine according to claim 32,in which the weight is slidably held on a shaft to adjust the bearingpressure of the thrust point against the base.
 34. A machine accordingto claim 32, arranged to be cam-actuated, comprising a cam surface; anda cam follower attached to an arm extending from the support; the camsurface normally holding the cam follower so that the thrust point isheld away from the fixed base, but when a lens is in contact with thebeveling wheel permitting the cam follower to pivot the pressure controlsupport until the thrust point is brought in contact with the fixedbase.
 35. In a lens edge-grinding and finishing machine having lens-edgegrinding, beveling and finishing wheels, and a rotatable, pivotable andreciprocable lens blank holder holding the lens blank in operativerelation to the said wheels for grinding, beveling and finishingthereof, to a size and pattern, the improvement which comprises a base;at least two apertured supports fixed on the base; at least one shaftextending through the apertures between the supports; and a movablecarriage attached to the shaft, which is arranged for reciprocabletransverse movement with respect to the supports in the apertures, andcarrying the lens blank holder for pivotal movement thereof towards andaway from the grinding wheel, and towards and away from the beveling andfinishing wheel, the carriage carrying a cam movable by a cam followerfixed to the base, for effecting and controlling reciprocable movementof the carriage and the shaft with respect to the grinding and bevelingand finishing wheels, and the cam having a circumferential groove inwhich the cam follower travels.
 36. A machine according to claim 35,having two parallel shafts extending between and sliding transverselythrough the apertures of the supports.
 37. A machine according to claim36, in which the shafts are supported on ball bushings disposed in thesupport apertures allowing reciprocable movement but not pivotingmovement thereof.